The present invention generally relates to rotary recording medium reproducing apparatuses capable of performing special reproduction, and more particularly to a rotary recording medium reproducing apparatus capable of effectively judging whether a kick pulse for kicking a reproducing element is to be generated in a micro-computer during special reproduction, to effectively use saved time for other processing operations.
Systems have been realized in which a recording system forms pits in accordance with information signal being recorded along a spiral track on a flat rotary recording medium (hereinafter referred to as disc), without forming a groove therein, and a reproducing stylus traces over along this track to reproduce the recorded information signal in response to variations in the electrostatic capacitance in a reproducing system.
In this system, since no groove is provided on the disc for guiding the reproducing stylus, pilot or reference signals are recorded on or in the vicinity of a track of the information signal, such as a video signal, on the disc. Upon reproduction, the reference signals are reproduced together with the video signal. Tracking servo control is carried out so that the reproducing stylus accurately traces along the track in response to the reproduced reference signals.
In the above disc, only one of a first and second reference signals fp1 and fp2 is recorded at an intermediate position between center lines of adjacent track turns. Moreover, the side on which the first and second reference signals are recorded with respect to one track turn changes over every one track turn. That is, when the first and second reference signals are respectively recorded on the right and left sides of one track turn, the relationship between the recorded positions of the reference signals is such that the second and first reference signals are respectively recorded on the right and left sides of adjacent track turns. Furthermore, a third reference signal for obtaining a changeover signal upon reproduction, is recorded for every track turn at recording changeover positions of the above first and second reference signals.
In a reproducing apparatus, a changeover operation is performed by use of the third reference signal reproduced upon obtaining of a tracking control signal from the reproduced first and second reference signals.
Since no grooves are provided in the above disc, the reproducing stylus can be transferred from one track to another without damaging the reproducing stylus or the disc. Accordingly, in addition to the special reproduction such as still reproduction, slow-motion reproduction, and quick-motion reproduction, the system is capable of performing a so-called random access in which the reproducing stylus is transferred to a desired position at high speed to reproduce the desired information.
During still reproduction of the above special reproduction, the reproducing stylus is kicked towards the outer side of the disc for every one revolution of the disc. Hence, the reproducing stylus repeatedly reproduces only one track turn of the spiral tracks formed on the disc. Moreover, during a slow-motion reproduction, the reproducing stylus is kicked towards the outer side of the disc by a quantity which is in accordance with the slow-motion ratio, to reproduce each track a plurality of times. Furthermore, during a quick-motion reproduction, the reproducing stylus is kicked towards the inner side of the disc by a quantity which is in accordance with the quick-motion ratio, to reproduce only a part of each track turn and successively transfer to the track on the inner side of the disc. In addition, during normal reproduction, the reproducing stylus is not kicked, and scans along the spiral track to perform reproduction.
Accordingly, during a special reproduction mode, the kick pulse is produced according to the specific special reproduction mode, to kick the reproducing stylus by use of the kick pulse. The micro-computer is supplied with a timing signal produced according to the reproduced third reference signal, and produces the above described kick pulse according to the special reproduction mode which is present. When the above kick pulse is produced, the micro-computer performs a judgment operation to judge whether the kick pulse is to be produced every time the timing signal is supplied to the micro-computer. Moreover, before the above judgement operation is performed, the above micro-computer discriminates the existence or non-existence of a changeover signal of the special reproduction mode, and signal processing related to the discrimination operation.
Hence, conventionally, as well be described hereinafter in conjunction with the accompanying drawings, the micro-computer produced the above kick pulse after judging whether the kick pulse is to be produced. Therefore, substantial time was required from the time the timing signal is generated until the kick pulse is generated. Moreover, separate time intervals existed for judging whether the kick pulse is to be produced and for producing the kick pulse. Thus, there was a disadvantage in that, until the next timing pulse is obtained after the kick pulse is generated, the time interval available for other operations such as signal processing was that much shorter.